This is a very intensely flavored, hearty filling. You can also eat it on its own as a Mexican rice/bean dish.
If using dry beans, soak them overnight first.
Roast and peel the poblano peppers. (Slice them lengthwise and put them on a cookie sheet under the broiler until the skins are black.) In a large, deep pot, saute the onions and garlic until the onions are nicely browned. Chop the peppers into large, chunky strips and add them in. Add the beans and 3-4 cups water. Add liquid smoke, chipotle peppers, oregano, and salt. Cover the pot. If using dried beans, let them boil, until nearly cooked (about 3 hours), adding water as needed. If using canned beans, go straight to adding the rice.
When you add the rice, be sure you have between 3 and 4 cups of liquid. (3 will be enough for the canned beans, but a little more will be needed if using dry beans.) If using dry beans, drain the liquid off and measure it, adding additional water or leaving some behind as required. Add the liquid back in, and add the rice. Cook until the rice is fully cooked and has absorbed the liquid, about 25 minutes.
It takes extra time, but using the dry beans is really good because they produce a rich gravy as they slowly cook that is hard to duplicate with canned beans.
*Note: If you can't find poblanos, substitute regular green chiles. If you can't find the chipotles in abodo sauce (its worth the effort to try and locate!), use 2 roasted jalapenos and 2 T of the hottest red chile powder you can get.
The recipe seems very hot as you're cooking it, but by the time the rice is cooked and the filling is put in burritos, its really pretty moderate. You can adjust to suit your taste. It makes a lot of burritos...I freeze them and use them for easy lunches for a long time--payback for the 4 hours cooking time!